The present invention relates to devices and methods for pulling elongate objects such as, e.g., stakes, pins, spikes, etc., from another object.
Numerous devices are know for removing stakes and other elongate objects which have been driven into another object such as, for example, the ground. Stakes, for example, are common at construction sites where forms for pouring concrete foundations, curbs, gutters, and the like are constructed using wooden boards held in place by surrounding stakes which are driven into the ground. Such stakes typically are installed in the ground so that their longitudinal axis is substantially vertical to horizontal, and they are typically driven into the ground with a hammer or like device for applying a downward force at one end of the stake. When stakes, large spikes, or similar objects are hammered into the ground or into other objects in this fashion, removal of the stakes can be a laborious task, especially when numerous stakes or spikes, etc. are involved. While devices are known which are configured to assist the laborer with the removal of such stakes, spikes, nails, etc., those devices are typically deficient in that they still require substantial physical force to be applied by the user, or they require heavy equipment to accompany the device or to serve as a component thereof to achieve the force necessary to facilitate removal of the elongate objects.
Thus, a need exists for a device which is configured to be hand-held and thus conveniently handled and transported, and which does not depend upon the user to supply substantial pulling force to the elongate object which is being pulled.
The present invention is deemed to fulfill this need in a highly efficient way by providing, among other things, a device which comprises: (a) at least one receiving means for receiving a free end portion of an elongate first object, the elongate first object being comprised of (i) the free end portion and (ii) an embedded end portion which is embedded in a second object, (b) at least one clamping means connected to or integral with the receiving means for applying at least one clamping force to the free end portion of the elongate first object, and (c) at least one jack which comprises a cylinder, a piston, a piston rod, and a base, the jack being connected to the receiving means so that when (i) the elongate first object is received by the receiving means, (ii) the base is in contact with the second object and (iii) a pressurized fluid is introduced into the jack to provide a separating force, the receiving means may be urged away from the second object while the clamping means applies the clamping force to the elongate first object, the amount of clamping force applied by the clamping means being proportional to the magnitude of the separating force. It will be understood that the elongate first object referred to herein may be comprised of a stake, pin or spike, or any other similar elongate object which has a free end portion and an embedded end portion which may be embedded into a second object such as, e.g., the ground or an object placed on the ground, or a wall structure. Merely for ease of reference herein, and without limiting the scope of this invention, unless otherwise indicated herein the elongate first object will be referred to hereinafter as a xe2x80x9cstakexe2x80x9d and the second object will be referred to as the xe2x80x9cgroundxe2x80x9d.
With respect to embodiments of this invention, it is preferred that the receiving means comprises a first hollow shaft segment which comprises at least one side wall, the side wall defining a lower passageway so that when received by the receiving means the stake may extend through the lower passageway and into at least a portion of the space within the first hollow shaft segment. It is also preferred that the side wall define one or more apertures, and that the clamping means comprises a bar which is sized, shaped and configured to extend through at least one of the apertures so that, when the receiving means is urged away from the ground, the bar cooperates with the side wall to clamp the stake between at least a portion of the side wall and at least a portion of the bar.
In another preferred embodiment, the bar is pivotally attached to the side wall and the first hollow shaft segment is surrounded by a housing through which the jack is connected to the first hollow shaft segment, the housing being sized, shaped and configured to pivotally actuate the bar when (i) the stake is received by the receiving means, (ii) the base is in contact with the ground and (iii) the jack is actuated to supply a separating force.
In yet another preferred embodiment, the side wall defines two substantially parallel and elongate lateral apertures disposed opposite one another and a third forwardly facing aperture, the lateral apertures being disposed so that their imaginary longitudinal axis is at an angle in the range between 0 and 90 degrees from horizontal, more preferably in the range of about 20 to about 80 degrees, most preferably in the range of about 45 to about 70 degrees. In addition, the bar of this preferred embodiment has two upper arm portions and a lower arm portion, the upper arm portions each being substantially perpendicular to the lower arm portion to form the shape of a xe2x80x9cTxe2x80x9d, and the bar is disposed within the hollow shaft segment so that each of the upper arms of the xe2x80x9cTxe2x80x9d bar extend through one of the lateral apertures respectively and the lower arm of the xe2x80x9cTxe2x80x9d bar extends through the forwardly facing aperture.
This invention also provides a method of removing a stake from the ground, the stake comprising a free end portion and an embedded end portion which is embedded in the ground, the method comprising: (a) surrounding at least a portion of the stake with a rigid material to which two pneumatic jacks are connected; (b) placing at least a portion of the pneumatic jacks in contact with the ground; (c) placing one or more clamping surfaces in contact with the stake; (d) actuating the jack to introduce a separating force between the stake and the ground while concurrently introducing a clamping force to the stake through the clamping surface, the clamping force being proportionate to the separating force.
These and other embodiments and features of the invention will become still further apparent from the ensuing description, appended claims and accompanying drawings.